This is a general sticky topic about success and failure methods on getting for example xen running inside VBox, all other such topics will be locked as people get confused and frustrated why it won't work.

As a general rule of thumb, most Virtualization packages do not support running another such package inside it, it is like trying to install XP inside a running XP, that will not work either.

There are some situations where this is possible with VBox and that is what this post is for, clearification, confirmation and information about the how, why and why not.

You CAN run Virtualization inside virtualization.What you can't do is use Virtualization Extensions (AMD-V, VT-X) inside a virtualized server.

Do make sure you mention VBox version number and other environment settings/hardware should you have a success story. It should be obvious discussions about running xen inside vmware will be removed as this is the VBox forum.

If you have a Xen Host, you cant run VirtualBox or VMWARE at the same time Xen is running. With a Xen Kernel its impossible to build the kernel modules for VirtualBox or VMWARE. So here the only way is the additionial installation of a standard kernel. To run VirtualBox or VMWARE you must boot with standard kernel.

I installed Virtualbox for Debian/Lenny running as a guest on Vmware ESX. I tried to add another Debian guest for VirtualBox. Installation started but get stucked when loading kernel. Is there any possibilities for this configuration?

No, this idea is the same as VB inside VB. VB itself won't run as Host on a Guest system, without some kind of special actions. That's what this topic is about, to find the ways to get virtualization inside a virtualization going. VB is just not the product to do this without some tweaks and hacks, just like any other virtualization app btw.

No luck. The inner VM (trying to run the Ubuntu live CD) stalls on startup. It runs the initial live CD menu, but then locks up, or gives IO APIC errors, or gives timeout messages once you tell it to boot from the "CD".

I've tried various combinations of enabling/disabling VT-D (and also IO APIC) in both virtualised environments, no difference.

One thing I'd like to try is removing the vbox tools from the (first) Ubuntu VM, but I can't see how to do this - any ideas?

No luck. The inner VM (trying to run the Ubuntu live CD) stalls on startup. It runs the initial live CD menu, but then locks up, or gives IO APIC errors, or gives timeout messages once you tell it to boot from the "CD".

I've tried various combinations of enabling/disabling VT-D (and also IO APIC) in both virtualised environments, no difference.

One thing I'd like to try is removing the vbox tools from the (first) Ubuntu VM, but I can't see how to do this - any ideas?

Don't bother. You can't run VB inside itself. Been there, done that. It will stall the moment it's past the BIOS splash.

Just curious, why would you run virtualization inside of virtualization? What are the benefits or what would be scenario where you would need this? Couldn't all the inner VM's just run in the outer instance? Or is the whole point that there is no real reason other than it's "just for fun" or "because I can".

No luck. The inner VM (trying to run the Ubuntu live CD) stalls on startup. It runs the initial live CD menu, but then locks up, or gives IO APIC errors, or gives timeout messages once you tell it to boot from the "CD".

I've tried various combinations of enabling/disabling VT-D (and also IO APIC) in both virtualised environments, no difference.

One thing I'd like to try is removing the vbox tools from the (first) Ubuntu VM, but I can't see how to do this - any ideas?

Don't bother. You can't run VB inside itself. Been there, done that. It will stall the moment it's past the BIOS splash.

This is not entirely true. If you have a processor with nested paging capabilities you can run VBox inside VBox. You can't use hardware virtualization in the inner VM though but raw mode will work just fine. This method was used to get VBox running on FreeBSD. So running a VM inside a VM is actually useful if you want to port the hypervisor to a new platform because you don't need to reboot the host and may loose data if something goes wrong (answering DaveHCYJ's question).

aeichner wrote:This is not entirely true. If you have a processor with nested paging capabilities you can run VBox inside VBox. You can't use hardware virtualization in the inner VM though but raw mode will work just fine. This method was used to get VBox running on FreeBSD.

But how many people has a nested paging capable CPU? AFAIK, only the Core i7 from Intel and some high end AMD's have it. Some users don't even have hardware-v available (either CPU or motherboard that doesn't support it).